Froment's Sign with ulnar neuropathy?

Video Description

Froment's sign is a physical exam maneuver found with an ulnar neuropathy. Therefore it can be found with ulnar nerve compression in the cubital tunnel (Cubital Tunnel Syndrome) or in Guyon's Canal (Ulnar Tunnel Syndrome).

It is performed by having the patient pinch a piece of paper with the thumb IP joint extended, and then pulling the paper away. If should be done with both hands side by side so compare them to each other.

In a hand with a ulnar neuropathy, adductor pollicis (ulnar n.) is deficient, and can not flex the MCP joint to give pinch strength with an extended IP joint. The hand compensates by recruiting the FPL, which is innervated by the median nerve, and flexing the IP joint to give pinch strength.

The result is, in a positive Froment's sign, the IP joint will flex (buckle) to try to give increased strength to the pinch.